1. Field of the Invention
The present invention relates to a tool kit. In particular, the present invention relates to a tool kit comprising a set of wrenches and a set of go-through type sockets.
2. Description of the Related Art
A typical socket wrench kit comprises a socket wrench and a plurality of sockets of various sizes. Each socket has a standard cavity in an end thereof for engaging with a drive column of the socket wrench. The cost for the user is relatively low, as a single socket wrench can be used to drive dozens of sockets. However, the torque imparted from the socket wrench is too large for some of the sockets. Further, the drive column of the socket wrench is an obstacle to operation in a limited space, such as the engine room of an automobile. Combination wrenches having a box end and an open end are the common option for users in this case. However, after driving the fastener through a certain angle, the user has to disengage the combination wrench from the fastener and then reengage with the fastener for next driving, and the procedure is repeated until the fastener is tightened/loosened to the desired extent. To solve this problem, ratchet type combination wrenches have been designed, allowing the user to freely turn the combination wrench in a reverse direction without driving the fastener. These small-head high-torque reversible combination wrenches are popular to automobile mechanics.
In one design of the small-head high-torque reversible combination wrenches, as illustrated in FIG. 3 of U.S. Pat. No. 5,295,422, the wrench includes a box end in which a wheel is rotatably mounted. The wheel includes a hexagonal inner periphery (or engaging surface) with six faces for engaging with an engaging surface of a bolt or a socket. However, the driving strength or torque is insufficient, as only six points are connected and engaged between the engaging surfaces of the wheel and the bolt (or socket).
To solve this problem, U.S. Pat. No. 5,295,422 discloses a wrench having a greater driving strength. The wrench comprises a handle portion and a head portion. A sleeve is rotatably engaged in the head portion and can be controlled to rotate in either direction. A go-through type socket includes a barrel engaged in an inner engaging surface of the sleeve. The user of the wrench of this type must purchase a set of go-through type sockets of various sizes, resulting in an additional cost. In use, as illustrated in FIG. 1 of the drawings, the wrench 10 can be used with a set of go-through type sockets 20a and 20b of various sizes. For a socket (e.g., socket 20a) including a driving hole 21a with a nominal size B greater than the nominal size A of the wrench 10, the torque imparted to the socket 20a is insufficient. On the other hand, for a socket (e.g., socket 20b) including a driving hole 21b with a nominal size C smaller than the nominal size A of the wrench 10, the torque imparted to the socket 20b is too large. Further, in a case that the socket 20b is selected for driving a fastener in a narrow, deep receptacle, the large head portion of the wrench 10 could not enter the narrow, deep receptacle. Driving of the fastener by the wrench 10 is thus impossible.